This invention relates to vehicle occupant restraint systems and more particularly to restraint systems for use in over the highway vehicles equipped with bunk beds.
Highway tractors are often equipped with small sleeping compartments, each containing a bunk for use by non-driving occupants. Under Federal regulations each bunk is required to be equipped with an occupant restraint system. Such restraint systems are intended for use when the vehicle is moving and a non-driving occupant is resting in a bunk. Frequently used restraint systems utilize flexible restraints in the form of harnesses or nettings that function by restricting the space in which an occupant lies or by providing restraint of the occupant during an emergency.
Typically, one end of such a restraint is anchored to the vehicle. The restraint is draped over the bunk bed and the other end is releasably attached to the bunk or to the vehicle at a location spaced from the anchor to provide an enclosure over the bunk bed. The other end typically has a releasable attachment, which is a buckle of the type used by the automotive seat belts.
Other types of restraint systems employ airbags which are installed in a horizontal and/or vertical deployment position with respect to an associated bunk. The airbags deploy when there is an impact or event sufficient to trigger the airbag mechanism. Airbag deployment most likely will not occur during emergency stops or other non-impact situations that could impart significant forward momentum or inertia to an occupant using the bed. Moreover, airbags are relatively complex systems and expensive to install compared to harness or netting restraint systems. Once an airbag has been deployed, maintenance is required to install a new airbag. Such maintenance obviously results in the vehicle being out of service until the maintenance is completed.
The geometry of a typical sleeping compartment in an over the highway tractor is such that upon impact bunk restraints are loaded in bending and shear. This bunk restraint loading contrasts with typical vehicle seat belts which are loaded in tension upon impact.
The reason bunk restraints and buckle systems are located in bending and shear rather than tension is that in positioning a buckle system at a location which would be convenient to bunk occupant. The geometry of the vehicle cab is such that in anchoring the belt to a portion of the cab which has sufficient physical integrity to withstand the force imposed upon an impact and the positioning of a buckle system such that it is readily accessible and convenient for use by an occupant, results in an arrangement in which the belt is not tensioned lineally between the belt, anchor and the buckle anchor. Rather as an occupant is thrust is forward relative to a vehicle that is experiencing a collision the restraining harness wraps around the occupant to some extent but cushioning is limited by a non yielding connection to the bunk. Accordingly the forces experienced by the occupant under such conditions are substantial and can be injurious accordingly it would be desirable to provide some yielding which absorbs some a the forces in a manner such that the deceleration of the inertia motion of the occupant is more gradual and such that the harness wraps around more of the occupant thus reducing the potential for injury and the severity of it.
In accordance with the present invention, a restraint system is provided in which a latch section of a buckle is positioned at a location convenient for attachment of a coacting tongue. The buckle latch section is pivotally connected to the frame of the bunk and maintained in its convenient position by a frangible sacrificial screw. In the event of a crash and the occupant being forced against a restraint connected to the buckle, the sacrificial screw is pulled from its connection to the frame such that the connected restraint assumes a position that has a section around the occupant and a further section which is lineal between the occupant and a remote anchor secured to the cab body.
In the preferred arrangement, the occupant restraint is in the form of a harness with at least two buckles anchoring the restraint. Both buckles are positioned at locations convenient for connection by a bunk occupant. Each of the buckles has a sacrificial screw or other frangible connection such that on impact portions of the harness assume lineal positions between the occupant and the remote vehicle connected anchors while the anchoring buckle pivots.
Preferably the harness is equipped with further straps which pull a section of the harness away from an occupant. The further straps function to produce a tent like arrangement which provides clearance for an occupant with out interfering with the proper functioning of the harness in the event of a collision.
With the harness of the present invention, in the event of collision inertia will cause an occupant to tend to continue to move in the direction the vehicle has been traveling. The result is the occupant will be thrust against the harness causing the harness to wrap around the occupant with a controlled amount of inertial force absorption as the frangible connections fail. When the occupant""s motion relative to the bunk is stopped, the buckle has pivoted forwardly and strap sections wrapped around the occupant while further sections extend lineally from the wrapped sections to the anchors.
Accordingly, the objects of the invention are to provide a novel and improved bunk occupant restraint system and a process of restraining an occupant in a bunk.